Aethemelikertes emunctorii Engel, 2021

Engel, Michael S. & Davis, Steven R., 2021, New genera of melikertine bees with facial modifications in Baltic amber (Hymenoptera: Apidae), Journal of Melittology 2021 (103), pp. 1-52 : 14-19

Aethemelikertes emunctorii Engel , new species

ZooBank: urn:lsid:zoobank.org:act:8D128194-DD96-463E-93A9-442DEA649B74

( Figs. 9–12 , 14, 16 , 17–18 , 20 )

DIAGNOSIS: As for the genus (vide supra).

DESCRIPTION: ⚲: Total body length (as preserved) 3.9 mm; forewing length (as preserved) 3.7 mm. Head slightly longer than wide, length (summit of vertex to clypeal apical margin) 1.20 mm, width (maximum width across compound eyes) 1.38 mm; compound eye length 0.82 mm; upper interorbital distance 0.95 mm, lower interorbital distance 0.84 mm; inner ocular margins largely straight, with faint arch about midlength, converging below; ocellar triangle broad, interocellar distance 0.40 mm. Scape length 0.50 mm, shorter than torulocellar distance. Mandible elongate, length 0.76 mm; labrum broader than long, basal width 0.44 mm, medial length 0.30 mm. Pronotum short, declivitous, without defined transverse dorsal ridge; pronotal lateral ridge absent; mesoscutum anterior border broadly rounded, anterior lip gently curving to meet posterior pronotal margin, not high over pronotal border; mesoscutum medial length 0.82 mm; intertegular distance 0.40 mm; mesoscutellum medial length 0.32 mm. Metatibia slender, length 1.40 mm, maximum width 0.37 mm; metabasitarsus longer than wide, length 0.43 mm, maximum width 0.27 mm. Forewing with basal vein (1M) basad 1cu-a, separated pterostigma longer than wide, maximum width at about midlength, margin inside marginal cell sloping to costal margin; marginal cell acutely rounded apically; basal vein (1M) straight; three submarginal cells (1rs-m present), second submarginal cell trapezoidal, posterior border strongly angled posteriorly (more strongly so than in Apini or many Meliponini ); 2Rs straight (somewhat similar to Apini and some Meliponini ); 3Rs shorter than r-rs, together about as long as 4Rs; 1rs-m weakly arched, 2rs-m strongly arched apicad in posterior half; wing membranes hyaline clear; veins dark brown.

Mandible smooth and shining; labrum smooth and shining; clypeus imbricate, coarsely so on disc and within clypeal basin, nearly granulose; face smooth to finely imbricate and shining (most of face poorly preserved and obscured by irregular surface material, but best view of integument along paraocular area of bee’s left compound eye and seen obliquely from below); sculpturing of mesosomal dorsum obscured by irregular material in air layer (apexes of setae and bristles emerge from this layer and so can be discerned); pleura largely finely imbricate (best observed on left mesepisternum and ventrally on propleura, right pleuron obscured by large reflective air bubble), otherwise surfaces, particularly preëpisternal area with similar irregular material layer adhering to integument; legs generally smooth to faintly imbricate; metatibial corbicular surface smooth and shining; bases of wings covered with similar irregular material extending from mesosoma; metasomal terga smooth and shining, with minute punctures at setal bases; sterna faintly imbricate with setigerous punctures apically.

Pubescence generally sparse; mandible with sparse, minute, erect, simple setae on outer surface proximally, longer, erect, simple setae scatered along length of lower margin; labrum with sparsely scatered, short, suberect to erect setae; clypeus without setae, except perhaps a few minute, simple setae at upper apical margin of clypeal basin; face with sparsely scatered, short, erect, simple setae intermixed with some minutely branched setae (seemingly present on lower face and less so on upper face); scape with minute, appressed, simple setae scatered along length; vertex with similar setae as those on face emerging from irregular debris obscuring surface, some on vertex somewhat thicker and bristle like, but short, distinctly shorter than median ocellar diameter; mesosomal dorsum largely obscured but long, erect, simple bristles present along lateral and posterior margin of mesoscutellum, and more sparsely on mesoscutellar disc; mespisternum with sparse, short, simple setae; pro- and mesocoxae, pro- and mesotrochanters, and pro- and mesofemora with sparse, minute, largely appressed, simple setae; pro- and mesotibiae with some longer, erect, simple setae more apically, particular on inner margins and outer surface of mesotibia (left mesotibia with a mass of pollen amid such setae on outer surface, interesting as such material is clearly not in a position for subsequent transfer to the corbicula as it is the inner metabasitarsal bristles that are most often used to scrape pollen from the body and forelegs and then pack the accumulated material into the corbicula, or squeezed between the metabasitarsi and into the corbicula via a pollen press in those lineages that have a metabasitarsal auricle: e.g., Michener et al., 1978); pro- and mesotarsi with abundant, longer, erect, simple bristles; metacoxa, metatrochanter, and metafemur similar to corresponding podites on midleg, except inner apical surface of metafemur with small ovoid patch of keirotrichia, finer and shorter than those of metatibia; metatibia with posterior margin with fringe of elongate, plumose (branches minute and along length of setal rachis) setae, setae as long as or longer than metatibial width, anterior margin with sparsely scatered simple setae and bristles, corbicular surface with sparsely scattered, erect, fine, long, simple setae; inner surface of metatibia with keirotrichiate zone covering most of surface except posterior, narrow, slightly depressed glabrate zone and broad, squarish, apical glabrate zone, apical glabrate zone slightly longer than apical width of metatibia; rastellum composed dense line of thick stiff bristles along entire inner apical margin of metatibia; metabasitarsus outer surface with sparse, fine, simple setae, inner surface and margins with abundant, elongate, erect to suberect, simple bristles; metasomal terga with sparse, minute, largely appressed, simple setae, such setae especially sparse on basal terga and becoming somewhat more numerous and slightly longer progressively on terga IV, V, and VI; sterna without setae except apically with erect, fine, simple setae on sterna II– IV, and more sparsely so on sterna V and VI.

Coloration largely not preserved or obscured, where evident seemingly brown to dark brown; otherwise microscopic separation of amber matrix from desiccated integument creating sufficient air space to form silver-looking reflection (common in many fossils, particularly from Baltic amber).

♀: Latet.

♂: Latet.

HOLOTYPE: ⚲, SMF Be 14262a ( SMF); Eocene ( Bartonian–Priabonian : a recent lithological and palynological analysis of the Yantarny borehole indicated a potential late Bartonian or early Priabonian age for the amber-bearing Wild Earth and Upper Blue Earth Members of the Prussian Formation , although the former has far less dispersed amber than the later, with the dinoflagellate and sporomorph assemblages largely indicating a late Bartonian age: Kasiński et al., 2020: 41, tables 1, 4) Baltic amber.

ETYMOLOGY: The specific epithet is taken from the Latin emunctorium, an acolyte’s candle snuffer, as an allusion to the bell- or scoop-like appearance of the clypeus.

Figures

Figures 9–10. Holotype worker of Aethemelikertes emunctorii, new genus and species, in Eocene (Bartonian) Baltic amber (SMF Be 14262a). 9. Ventral view. 10. Slightly obliquely dorsal facial view emphasizing upper, slightly scalloped margin of clypeal basin.

Figure 11. X-ray µCT scan of holotype worker of Aethemelikertes emunctorii, new genus and species (SMF Be 14262a), lateral view. Note that scan resolution was insufficient to resolve most setae.

Figure 12. Ventral facial view of holotype worker of Aethemelikertes emunctorii, new genus and species (SMF Be 14262a). Note carinae demarcating lateral margins of basin extending to clypeal apex where clypeus extends laterally around base of labrum.

Figures 13–16. X-ray µCT scans of heads of holotype workers of Succinapis micheneri Engel (AMNH B-JH103) and Aethemelikertes emunctorii, new genus and species (SMF (Be 14262a), in Baltic amber; yellow highlights disc and modification of clypeus, orange highlights labrum. 13. Facial view of S. micheneri. 14. Facial view of A. emunctorii. 15. Oblique profile of S. micheneri. 16. Oblique profile of A. emunctorii. Note that scan resolution was insufficient to resolve most setae.

Figures 17–18. X-ray µCT scans of hindleg of Aethemelikertes emunctorii, new genus and species (SMF Be 14262a). 17. Outer (prolateral) view. 18. Inner (retrolateral) view. Note that scan resolution was insufficient to resolve most fine setae and setal details.

Figures 19–20. Inner (retrolateral) surfaces of metatibiae of Haidomelikertes, new genus, and Aethemelikertes, new genus. 19. Haidomelikertes uraeus, new species, holotype worker (SMF Be 14263a). 20. Aethemelikertes emunctorii, new species, holotype worker (SMF Be 14262a).